/*
 * Copyright 2001-2004 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.log4j;

import org.apache.log4j.helpers.NullEnumeration;
import org.slf4j.LoggerFactory;
import org.slf4j.Marker;
import org.slf4j.MarkerFactory;
import org.slf4j.spi.LocationAwareLogger;

import java.util.Enumeration;

/**
 * <p>
 * This class is a minimal implementation of the original
 * <code>org.apache.log4j.Category</code> class (as found in log4j 1.2) by
 * delegation of all calls to a {@link org.slf4j.Logger} instance.
 * 
 *
 * <p>
 * Log4j's <code>trace</code>, <code>debug()</code>, <code>info()</code>,
 * <code>warn()</code>, <code>error()</code> printing methods are directly
 * mapped to their SLF4J equivalents. Log4j's <code>fatal()</code> printing
 * method is mapped to SLF4J's <code>error()</code> method with a FATAL marker.
 *
 * @author S&eacute;bastien Pennec
 * @author Ceki G&uuml;lc&uuml;
 */
@SuppressWarnings("rawtypes")
public class Category {

	private static final String CATEGORY_FQCN = Category.class.getName();

	private String name;

	protected org.slf4j.Logger slf4jLogger;
	private org.slf4j.spi.LocationAwareLogger locationAwareLogger;

	private static Marker FATAL_MARKER = MarkerFactory.getMarker("FATAL");

	Category(String name) {
		this.name = name;
		slf4jLogger = LoggerFactory.getLogger(name);
		if (slf4jLogger instanceof LocationAwareLogger) {
			locationAwareLogger = (LocationAwareLogger) slf4jLogger;
		}
	}

	public static Category getInstance(Class clazz) {
		return Log4jLoggerFactory.getLogger(clazz.getName());
	}

	public static Category getInstance(String name) {
		return Log4jLoggerFactory.getLogger(name);
	}

	public final Category getParent() {
		return null;
	}

	/**
	 * Returns the obvious.
	 *
	 * @return
	 */
	public String getName() {
		return name;
	}

	public Appender getAppender(String name) {
		return null;
	}

	public Enumeration getAllAppenders() {
		return NullEnumeration.getInstance();
	}

	/**
	 * Return the level in effect for this category/logger.
	 *
	 * <p>
	 * The result is computed by simulation.
	 *
	 * @return
	 */
	public Level getEffectiveLevel() {
		if (slf4jLogger.isTraceEnabled()) {
			return Level.TRACE;
		}
		if (slf4jLogger.isDebugEnabled()) {
			return Level.DEBUG;
		}
		if (slf4jLogger.isInfoEnabled()) {
			return Level.INFO;
		}
		if (slf4jLogger.isWarnEnabled()) {
			return Level.WARN;
		}
		return Level.ERROR;
	}

	/**
	 * Returns the assigned {@link Level}, if any, for this Category. This
	 * implementation always returns null.
	 *
	 * @return Level - the assigned Level, can be <code>null</code>.
	 */
	final public Level getLevel() {
		return null;
	}

	/**
	 * @deprecated Please use {@link #getLevel} instead.
	 * @return a Level
	 */
	final public Level getPriority() {
		return null;
	}

	/**
	 * Delegates to {@link org.slf4j.Logger#isDebugEnabled} method in SLF4J
	 * 
	 * @return true if this logger is enabled for the level DEBUG
	 * 
	 */
	public boolean isDebugEnabled() {
		return slf4jLogger.isDebugEnabled();
	}

	/**
	 * Delegates to {@link org.slf4j.Logger#isInfoEnabled} method in SLF4J
	 * 
	 * @return true if this logger is enabled for the level INFO
	 */
	public boolean isInfoEnabled() {
		return slf4jLogger.isInfoEnabled();
	}

	/**
	 * Delegates to {@link org.slf4j.Logger#isWarnEnabled} method in SLF4J
	 * 
	 * @return true if this logger is enabled for the level WARN
	 */
	public boolean isWarnEnabled() {
		return slf4jLogger.isWarnEnabled();
	}

	/**
	 * Delegates to {@link org.slf4j.Logger#isErrorEnabled} method in SLF4J
	 * 
	 * @return true if this logger is enabled for the level ERROR
	 */
	public boolean isErrorEnabled() {
		return slf4jLogger.isErrorEnabled();
	}

	/**
	 * Determines whether the priority passed as parameter is enabled in the
	 * underlying SLF4J logger. Each log4j priority is mapped directly to its SLF4J
	 * equivalent, except for FATAL which is mapped as ERROR.
	 *
	 * @param p the priority to check against
	 * @return true if this logger is enabled for the given level, false otherwise.
	 */
	public boolean isEnabledFor(Priority p) {
		switch (p.level) {
		case Level.TRACE_INT:
			return slf4jLogger.isTraceEnabled();
		case Level.DEBUG_INT:
			return slf4jLogger.isDebugEnabled();
		case Level.INFO_INT:
			return slf4jLogger.isInfoEnabled();
		case Level.WARN_INT:
			return slf4jLogger.isWarnEnabled();
		case Level.ERROR_INT:
			return slf4jLogger.isErrorEnabled();
		case Priority.FATAL_INT:
			return slf4jLogger.isErrorEnabled();
		}
		return false;
	}

	void differentiatedLog(Marker marker, String fqcn, int level, Object message, Throwable t) {

		String m = convertToString(message);
		if (locationAwareLogger != null) {
			locationAwareLogger.log(marker, fqcn, level, m, null, t);
		} else {
			switch (level) {
			case LocationAwareLogger.TRACE_INT:
				slf4jLogger.trace(marker, m, (Throwable) t);
				break;
			case LocationAwareLogger.DEBUG_INT:
				slf4jLogger.debug(marker, m, (Throwable) t);
				break;
			case LocationAwareLogger.INFO_INT:
				slf4jLogger.info(marker, m, (Throwable) t);
				break;
			case LocationAwareLogger.WARN_INT:
				slf4jLogger.warn(marker, m, (Throwable) t);
				break;
			case LocationAwareLogger.ERROR_INT:
				slf4jLogger.error(marker, m, (Throwable) t);
				break;
			}
		}
	}

	/**
	 * Delegates to {@link org.slf4j.Logger#debug(String)} method of SLF4J.
	 * 
	 * @param message a message to log
	 */
	public void debug(Object message) {
		differentiatedLog(null, CATEGORY_FQCN, LocationAwareLogger.DEBUG_INT, message, null);
	}

	/**
	 * Delegates to {@link org.slf4j.Logger#debug(String,Throwable)} method in
	 * SLF4J.
	 * 
	 * @param message a message to log
	 * @param t       a throwable to log
	 */
	public void debug(Object message, Throwable t) {
		differentiatedLog(null, CATEGORY_FQCN, LocationAwareLogger.DEBUG_INT, message, t);
	}

	/**
	 * Delegates to {@link org.slf4j.Logger#info(String)} method in SLF4J.
	 * 
	 * @param message a message to log
	 */
	public void info(Object message) {
		differentiatedLog(null, CATEGORY_FQCN, LocationAwareLogger.INFO_INT, message, null);
	}

	/**
	 * Delegates to {@link org.slf4j.Logger#info(String,Throwable)} method in SLF4J.
	 *
	 * @param message a message to log
	 * @param t       a throwable to log
	 */
	public void info(Object message, Throwable t) {
		differentiatedLog(null, CATEGORY_FQCN, LocationAwareLogger.INFO_INT, message, t);
	}

	/**
	 * Delegates to {@link org.slf4j.Logger#warn(String)} method in SLF4J.
	 * 
	 * @param message a message to log
	 * 
	 */
	public void warn(Object message) {
		differentiatedLog(null, CATEGORY_FQCN, LocationAwareLogger.WARN_INT, message, null);
	}

	/**
	 * Delegates to {@link org.slf4j.Logger#warn(String,Throwable)} method in SLF4J.
	 * 
	 * @param message a message to log
	 * @param t       a throwable to log
	 * 
	 */
	public void warn(Object message, Throwable t) {
		differentiatedLog(null, CATEGORY_FQCN, LocationAwareLogger.WARN_INT, message, t);
	}

	/**
	 * Delegates to {@link org.slf4j.Logger#error(String)} method in SLF4J.
	 * 
	 * @param message a message to log
	 * 
	 */
	public void error(Object message) {
		differentiatedLog(null, CATEGORY_FQCN, LocationAwareLogger.ERROR_INT, message, null);
	}

	/**
	 * Delegates to {@link org.slf4j.Logger#error(String,Throwable)} method in
	 * SLF4J.
	 * 
	 * @param message a message to log
	 * @param t       a throwable to log
	 * 
	 */
	public void error(Object message, Throwable t) {
		differentiatedLog(null, CATEGORY_FQCN, LocationAwareLogger.ERROR_INT, message, t);
	}

	/**
	 * Delegates to {@link org.slf4j.Logger#error(String)} method in SLF4J.
	 * 
	 * @param message a message to log
	 * 
	 */
	public void fatal(Object message) {
		differentiatedLog(FATAL_MARKER, CATEGORY_FQCN, LocationAwareLogger.ERROR_INT, message, null);
	}

	/**
	 * Delegates to {@link org.slf4j.Logger#error(String,Throwable)} method in
	 * SLF4J. In addition, the call is marked with a marker named "FATAL".
	 * 
	 * @param message a message to log
	 * @param t       a throwable to log
	 *
	 */
	public void fatal(Object message, Throwable t) {
		differentiatedLog(FATAL_MARKER, CATEGORY_FQCN, LocationAwareLogger.ERROR_INT, message, t);
	}

	protected void forcedLog(String FQCN, Priority p, Object msg, Throwable t) {
		log(FQCN, p, msg, t);
	}

	// See also http://jira.qos.ch/browse/SLF4J-159
	public void log(String FQCN, Priority p, Object msg, Throwable t) {
		int levelInt = priorityToLevelInt(p);
		differentiatedLog(null, FQCN, levelInt, msg, t);
	}

	public void log(Priority p, Object message, Throwable t) {
		int levelInt = priorityToLevelInt(p);
		differentiatedLog(null, CATEGORY_FQCN, levelInt, message, t);
	}

	public void log(Priority p, Object message) {
		int levelInt = priorityToLevelInt(p);
		differentiatedLog(null, CATEGORY_FQCN, levelInt, message, null);
	}

	private int priorityToLevelInt(Priority p) {
		switch (p.level) {
		case Level.TRACE_INT:
		case Level.X_TRACE_INT:
			return LocationAwareLogger.TRACE_INT;
		case Priority.DEBUG_INT:
			return LocationAwareLogger.DEBUG_INT;
		case Priority.INFO_INT:
			return LocationAwareLogger.INFO_INT;
		case Priority.WARN_INT:
			return LocationAwareLogger.WARN_INT;
		case Priority.ERROR_INT:
			return LocationAwareLogger.ERROR_INT;
		case Priority.FATAL_INT:
			return LocationAwareLogger.ERROR_INT;
		default:
			throw new IllegalStateException("Unknown Priority " + p);
		}
	}

	protected final String convertToString(Object message) {
		if (message == null) {
			return (String) message;
		} else {
			return message.toString();
		}
	}

	public void setAdditivity(boolean additive) {
		// nothing to do
	}

	public void addAppender(Appender newAppender) {
		// nothing to do
	}

	public void setLevel(Level level) {
		// nothing to do
	}

	public boolean getAdditivity() {
		return false;
	}

	public void assertLog(boolean assertion, String msg) {
		if (!assertion)
			error(msg);
	}

}
